The present invention relates to an igniter assembly used in an inflator of an airbag device or a seat belt device, an inflator including the igniter assembly, and an airbag device and a seat belt device including the inflator.
In an igniter assembly assembled in an inflator of an airbag device, if an igniter is energized, high-temperature reaction gas is rapidly generated and a gas generating agent of the inflator starts to react with this reaction gas. Thus, the inflator generates a large amount of gas, and an airbag rapidly expands by this gas.
A conventional igniter assembly of an inflator will be described with reference to FIGS. 10(a)-10(c). FIG. 10(a) is a cross-sectional view taken along the axial direction of the igniter assembly, FIG. 10(b) is a cross-sectional view taken along the axial direction of a collar, and FIG. 10(c) is an enlarged cross-sectional view of the interface between the collar and a resin.
The igniter assembly 10A includes an igniter 20, a substantially cylindrical collar 30A for holding the igniter 20, and the resin 40 for joining the igniter 20 to the collar 30A. The igniter 20 has a head portion 21 containing a reaction agent and pins 22 and 23 protruded and extended from the head portion 21 as conducting terminals. The collar 30A has a cylindrical main body 31, a collar portion 32 provided inward at the inner circumferential surface of the main body 31, and a cylindrical surrounding wall portion 33 extended from one end of the shaft of the main body 31. A surface 32b of the collar portion 32 at the side of the surrounding wall portion 33 is a radial surface extended in a radiant direction perpendicular to the shaft of the main body 31.
The head portion 21 of the igniter 20 is disposed in the surrounding wall portion 33 and the pins 22 and 23 are inserted into the main body 31 through an internal hole of the collar portion 32.
The resin 40 is filled between the igniter 20 and the inside of the surrounding wall portion 33 and the inner circumferential surface 32a of the internal hole of the collar portion 32 by injection molding or the like.
The resin 40 is filled between the igniter 20 and the collar 30A, but then shrinks in the arrow direction A of FIG. 10(c) during cooling. Accordingly, as shown in FIG. 10(c), a gap C may be generated between the resin 40 and the inner circumferential surface of the surrounding wall portion 33 and the inner circumferential surface 32a of the collar portion 32. This gap C may function as a passage for leaking gas at the time of operation of the inflator.
Japanese Unexamined Patent Application Publication No. 2004-293835 discloses a construction in which a cylindrical protrusion is provided on a collar such that a gap extended from the inner circumferential surface of the collar to the outer surface of an igniter is not generated although resin is shrunk. However, in this case, the cost of producing the collar increases by forming the protrusion.
An object of the present invention therefore is to provide an igniter assembly which can prevent a gap from being generated due to shrinkage of resin, and which has an easily manufactured collar. Another object of the invention is to provide an inflator using the igniter assembly, and an airbag device and a seat belt device including the inflator.
Further objects and advantages of the invention will be apparent from the following description of the invention and the associated drawings.